Electrical behavior of chemically grown lanthanum ferrite thin films

Abstract

Perovskite structured oxides are important functional materials often used for the development of modern devices. To extend their applicability, these materials need to be scalably and efficiently grown in the form of thin films. In this work, perovskite structured thin films of nanograined LaFeO 3 (LFO) were chemically grown using polymeric precursors on Pt substrates. The thin films were characterized by X-ray diffraction, field-emission scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The electrical properties of the films were also measured. The homogeneous LFO thin films synthesized at a sintering temperature of 500 1C in 2 h contained grains with lateral dimensions of about 68 nm and 356 nm in thickness. The dielectric permittivity and dielectric loss measurements of the sample indicated only a slight dispersion in the frequency because of the lower two-dimensional stress in the plane of the film. The nanograined LFO semiconductor thin films showed a room temperature magnetic coercive field, which rendered them magnetically soft. The electrical characterization of the films, including temperature-dependent conductivity and thermopower confirmed p-type conduction and the mobility activation energy was measured to be 0.96 eV. A strong magnetization with a remnant magnetization of $60 emu/g was observed in the LFO films, indicating the uncompensated spin magnets moments of the Fe 3 þ ions.

Preparation and characterization of lanthanum-based perovskite oxides LaMO3 (M=Fe, Cr, Mn) thin films by electrophoretic deposition

“…The porosity values were found to be approximately 4.5 %, 6.6 %, and 3 % for LaFeO , 3 LaCrO 3 and LaMnO , 3 respectively. Similar observations, characterized by pore-free surfaces, were reported by Ranieri et al [42] for LaFeO 3 thin films and by Pan et al [43] for LaCrO 3 thin films, both prepared using the solgel method. Additionally, Okuyucu et al [44] observed a compact and less porous surface in LaMnO 3 thin film, with a grain size of about 50 nm, aligning with the findings of our study. )…”

Role of morphological characteristics on the conductive behavior of LaNiO3 thin films

“…LNO films were prepared with the polymeric precursor method and the synthesis conditions used in this work were based on our previous works [16][17][18]. The polymeric solution was prepared at a molar ratio of metal: citric acid: ethylene glycol of 1:4:8.…”

La0.5Sm0.5FeO3: a new candidate for magneto-electric coupling at room temperature

“…The dielectric constant and dissipation factor, at 1 MHz, were found to be 358 and 0.036, respectively. The LFO:Sm film had higher relative dielectric permittivity when compared with those previously reported films [4]. The observed behaviour of dielectric permittivity may be associated with significant effect on the overall microstructure of the system [24] and due to the ability to switch the electric dipoles with the frequency of the applied field.…”

“…The perovskites are of particular interest for their relatively simple crystal structure with many diverse properties viz., magnetic, piezoelectric, optical, catalytic and dielectric. In our recent work [4], we have shown that LFO exhibited p-type conduction (i.e., the holes were the dominant charge carriers). But the room temperature magnetization of this material is not high enough.…”

“…LaFeO 3 is a perovskite oxide [7,8], which has been extensively studied because of its potential applicability in gas sensors, electrodes of solid-state fuel cells, spin valves, and other exchange bias applications in magnetic memory, or for oxygen sensing [4,[7][8][9][10][11][12][13][14][15]. LFO with antiferromagnetic characteristics [9,10] crystallizes in an orthorhombically distorted perovskite structure with lattice parameters a = 5.557 Å, b = 5.5652 Å, and c = 7.8542 Å [14].…”